Device for terminating an electrical cable

ABSTRACT

A device (1) comprising a flexible and resilient sleeve (2) made of rubber, rubber-like, plastics or similar material and a metal end termination (3) which has a screw thread connection with an electrical component (4) in the form of a multi-pin connector or plug. The end termination (3) has an interface (5) for conductors or wires of the multi-core cable and a body (6) which has a tapered entry (7) in which is received the sleeve (2) and metal braids (8) which screen the cable (9). There is a seal in the form of an O-ring (10) at the blind end of the entry (7) to prevent moisture getting into the cable. The other end of the sleeve (2) from the body (6) is mechanically secured as by adhesive to the other surface of an outer sheath of the multi-core cable (9) at anchor (11). To re-enter connection, the termination (3) and component (4) are unscrewed and pulled apart in direction (x) so that the convulsions of the sleeve (2) bunch up. An embodiment is described in which a metallic screen is independent of end termination (3) and is not retracted when the termination is retracted, the screen having a ring which has complementary mating engagement with the end termination.

TECHNICAL FIELD OF INVENTION

The invention relates to a device for terminating an electrical cablesuch as a multi-core electrical cable.

BACKGROUND ART

Electrical cables such as of the multi-core kind are often connectedwith electrical components such as multi-pin connectors. If a connectionhas to be modified or checked, it is usual not to be able to carry outsuch a task without destroying the interface and hence vitiating theintegrity of the design characteristics of the connector.

DISCLOSURE OF INVENTION

It is an object of the invention to seek to mitigate this disadvantage.

According to the invention there is provided a device for terminating anelectrical cable, comprising a flexible and resilient sleeve forsecuring to an outer surface of the cable and an end termination whichis engageable with and disengeable from an electrical component to whichthe cable is to be connected, the arrangement being such that when theend termination is disengaged from the component the device can beretracted effectively by shortening the sleeve and withdrawing the endtermination whereby to expose the cable connection.

Using the invention it is possible to provide an electrical connectionwhich is re-enterable to enable rework to be carried out on an endtermination interface.

The sleeve may be convoluted, preferably with helical convolutions, toenable the sleeve to be compressed axially when the device is retracted.This is a relatively simple yet efficient construction.

The end termination may have screw threads for engagement with acomplementary screw thread of the electrical component. Thisconstruction is relatively simple yet provides for efficient engagementand disengagement.

The end termination may include a seal such as an "O"-ring. Such a sealprotects the interior of the device against penetration by moisture, soobviating electrical short circuits.

The device may include means to bond mechanically with a metallic screenof the cable. This construction, particularly where the cable is ascreened multi-core cable, provides for EMC screening through the endtermination.

It will be understood that the invention extends to a cable including adevice as hereinbefore defined.

Devices for terminating an electrical cable, embodying the invention,are hereinafter described, by way of example, with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a part sectional view of a first device according to theinvention mounted on the end of a multi-core electrical cable andconnected with an electrical component in the form of a multi-pinconnector;

FIG. 2 is a view, to a smaller scale than that of FIG. 1, of the cableand device;

FIGS. 3 and 3A show, in part longitudinal section and enlarged relativeto FIG. 1, a second embodiment of device according to the invention;

FIGS. 4 and 4A show, also in part longitudinal section and enlargedrelative to FIG. 1, a third embodiment of device according to theinvention; and

FIG. 5 shows a device according to the invention in use.

Referring to the drawings the device 1 shown comprises a flexible andresilient sleeve 2 made of rubber, rubber-like, plastics or similarmaterial and a metal end termination 3 which has a screw threadconnection with an electrical component 4 in the form of a multi-pinconnector or plug. The end termination 3 has an interface 5 forconductors or wires of the multi-core cable and a body 6 which has atapered entry 7 in which is received the sleeve 2 and metal braids 8which screen the cable 9. There is a seal in the form of an "O"-ring 10at the blind end of the entry 7 to prevent moisture getting into thecable. The other end of the sleeve 2 from the body 6 is mechanicallysecured as by adhesive to the outer surface of an outer sheath of themulti-core cable 9 at anchor 11.

In use, the sleeve 2 is secured as shown and the other end, with thebraid, is drawn into the body 6 by screwing, so forming a firmmechanical bond over 360°, which ensures screening of the connection andthe cores connected in the interface 5, itself mounted in the body 6.The end termination 3 is then screw engaged with the component 4 to makea complete device 1 embodying the invention. Should it be necessary tore-enter the connection to carry out further work thereon, the endtermination 3 and component 4 are disengaged by unscrewing and bysliding the termination 3 to the right (as viewed in FIG. 1) whichmovement is accommodated by an axial compression and hence effectiveshortening of the sleeve 2, the sleeve being anchored on the cable at11. When the rework has been completed, the end termination 3 is movedto the left (FIG. 1) and reconnected with the component 4. Theserespective movements are shown by the double-headed arrows "X" and "Y".

Referring now to FIGS. 3 and 3A, a second embodiment of device is shown,FIG. 3 showing anchor 21, the end termination 3 being identical to thatshown in FIG. 1, the component 4 being omitted for clarity in FIGS. 3and 3A. The anchor 21 comprises a support ring 22 for cable bundleconductors 23 and cable bundle screen(s) 24 a screen ring 25 and a metalsleeve 26 which is swaged down onto cable bundle outer sheath 27 at 28to provide a firm connection of all the components which neverthelessare all fully screened.

In use, to re-enter the end termination provided by the device it ismerely necessary as in the first embodiment, to unscrew the endtermination from the connector 4 to expose the wires of the cable bundleafter the end termination is retracted in the direction of the arrow"X". When the work is complete, the end termination is moved in thedirection of the arrow "Y" to be screw connected with the connector, sothat the device is complete and electrically screened and insulated oncemore ready for use. The convolution of the conduit allow this retractionand re-application.

Teeth 29 of body 6 in both embodiments ensure a positive grip or seatingfor braid or screen 24 at the end termination while tooth 30 has thesame function at the securing end 21 of the end termination adjacent thesleeve 26.

Referring to FIGS. 4 and 4A there is shown a third embodiment 40 of endtermination 31. In this embodiment 40 there is an end termination 3screw-engageable with a connector (not shown) as in the embodiments ofFIGS. 1 and 3, 3A, but in this case a metal braid screen 41 of thedevice for the conductors/wires of the cable 42 is independent of thebody 6. To achieve this, the screen 41 is secured to a screen ring 43which has an enlarged head portion 44 which has a chamfered or inclinedsurface 45 which mates with a complementary surface 46 of the body 6,the surface 46 being internally of the body 6. The body 6 has teeth 47by which the convoluted conduit 48 is firmly received in the body 6 ofthe device. At the other end of the device, the braid 41 is received ina screen ring 49 and overlies the braid or braids 50, the convolutedsleeve 48, screen ring 49, overlapping ends of the screen 41 andbraid(s) 50 and outer sheath 51 of the cable 42 being firmly received ina metal sleeve 52 which is swaged down onto the outer sheath 51 toprovide a secure fixing of all the components, which fixing is enhancedby circumferential notches or teeth 53 in the sleeve 42 so that when itis swaged down the convoluted conduit and outer sheath are forced intoteeth to trap them and obviate withdrawal.

FIG. 4 shows the device as it is when the end termination 3 isscrew-engaged with the component in which the conductors of the cable 42are secured. The convolutions 48 are separate and the mating surfaces45, 46 of the screen ring 44 and body 6 are in firm metal-to-metalcontact so providing an integral screening (EMC) effect. When it isdesired to re-enter the connection, the end termination 3 is unscrewedfrom the component and withdrawn to the right (as viewed) in thedirection of arrow "X". The convolutions bunch up to allow suchmovement, but as the movement takes place, the body 6 is withdrawn fromthe screen ring 44 so that that ring 44 and the screen 41 to which it isattached stay where they are. They are thus "floating" or independent.This means that the conduit 48 can be withdrawn much further to theright because the screen 41 is not pulled back with it, and does notinterfere with the retraction of the device and bunching up of theconvolutions. This means that there is a much larger work length of thecable exposed for effecting the re-entry work. When it is desired tore-establish end termination after re-entry work has been completed theend termination 3 as moved to the left as viewed in the direction ofarrow "Y" and is screw-engaged with the component, so completing thedevice. Movement back to the FIG. 4 position from the FIG. 4A positionre-establishes firm metal-to-metal contact between the inclined matingsurfaces 45 and 46 of the screen ring 44 and body 6.

FIG. 5 shows schematically the manual retraction of the end terminationfom the component or connector for access to the rear thereof tofacilitate circuit repair or re-routing. The individual conductors 54 ofthe cable are shown, and the re-entrability provided by the devicesenables cables to be re-routed or damaged ones to be repaired. Moreover,this re-entrability also allows for electrical checks such as DCresistance to be carried out.

In all cases full 360° EMC screening is obtained.

I claim:
 1. A device for terminating an electrical cable, comprising aflexible and resilient sleeve for securing to an outer surface of thecable, and an end termination engageable with and disengageable from anelectrical component to which the cable is to be connected, thearrangement being such that when the end termination is disengaged fromthe component the device can be retracted effectively by shortening thesleeve and withdrawing the end termination whereby to expose the cableconnection, and tooth means of a hollow body which forms the endtermination for effecting a mechanical bond with a metallic screen whichscreens the cable.
 2. A device according to claim 1, the end terminationhaving a screw thread for engagement with a complementary screw threadof the electrical component.
 3. A device according to claim 1, thesleeve being convoluted.
 4. A device according to claim 3, theconvolutions being helical.
 5. A device according to claim 1, the endtermination including a seal whereby the interior of the device isprotected from penetration by moisture.
 6. A device according to claim5, the seal comprising an "O"-ring.
 7. A device for terminating anelectrical cable, comprising a flexible and resilient sleeve forsecuring to an outer surface of the cable, and an end terminationengageable with and disengageable from an electrical component to whichthe cable is to be connected, the arrangement being such that when theend termination is disengaged from the component the device can beretracted effectively by shortening the sleeve and withdrawing the endtermination whereby to expose the cable connection, said deviceincluding a metallic screen secured at an end adjacent the endtermination to a screen ring, the screen ring and end termination havingcomplimentary mating surfaces whereby when the end termination andcomponent are engaged the complementary mating surfaces are inengagement and when the end termination and component are separated themating surfaces disengage.
 8. A device according to claim 7, wherein thecomplementary mating surfaces are respectively inclined surfaces of theend termination and screen ring.
 9. An electrical cable according toclaim 7, comprising a multi-core cable.
 10. An electrical cableaccording to claim 8 connected to an electrical component comprising amulti-pin connector.